Foot drop, drop foot, and foot dangle are terms which have been employed to describe ankle and toe dorsiflexor paresis resulting in the inability to raise the foot at the ankle, such that the foot inclines towards and scrapes the ground when walking. Dorsiflexion is the motion the ankle joint makes when the foot points upward. This motion needs to occur when the foot comes off the ground so that the toes do not drag.
Foot drop makes walking difficult as the toes tend to drag on the ground which leads to tripping and instability. Patients adapt to this by using their hip muscles to exaggerate lifting the foot above the ground (known as a “steppage gait”) or by swinging their leg outward so that the foot can clear the ground (known as “circumduction”).
A common remediation technique for foot drop involved the employment of an ankle foot orthosis, or brace. The goal of bracing is to provide patients with a more normal and comfortable gait. These devices often require professional fitting, which may imply taking of impressions of the affected foot, and customized shoes. Significant delays can occur between the fitting and receipt of the customized orthosis.
Several braces have been developed for foot drop. Short leg fixed braces, for instance U.S. Pat. No. 5,429,588, fit into the footwear, do not flex at ankle joint, and do not allow plantar flexion nor dorsiflexion, i.e. they do not provide quite as natural of a gait. Dorsiflexion assist short leg braces are similar to short leg fixed braces but with a spring-like hinge that acts to raise the foot, i.e. dorsiflex the ankle when the foot comes off of the ground. It offers the advantage of a more normal gait pattern. Solid ankle braces, with or without posterior stop, also fit inside the footwear and have a hinge that allows normal dorsiflexion. They can or cannot allow plantarflexion, i.e. it can or cannot let the foot point downward. Energy return braces also fit inside the footwear and use a natural flex built into the material of the brace to provide assist in dorsiflexion. These braces are often made of polymers or carbon graphite materials.